Paper clip



Oct. 9, 1962 K. LORBER PAPER CLIP Filed April 9, 1958 79.2 F/g Ffgy iii i! l! U! auf f. Jff/,

ATTQRNEY United tates Faterrt 3,057,028 PAPIER CLIP Kurt Lorber, Aichelberg, Esslingen (Neckar), Germany Filed Apr. 9, 1958, Ser. No. 727,454 Claims priority, application Germany Apr. 17, 1957 16 Claims. (Cl. 24'66) The present invention relates to a method of producing paper clips and similar articles of manufacture consisting of plastic or similar moldable materials, and more particularly to such clips which have two or more substantially U-shaped clamping arms.

In order to simplify the following description, the term clips or paper clips as used therein is meant also to include similar articles of manufacture and the term plastic material any similar moldable material suitable for the purposes of the invention.

It is an object of the present invention to provide a new method of producing paper clips of plastic materials, and to make such clips of a great solidity and strength, as well as of a high resiliency.

Another object of the present invention is to provide a paper clip of a particular shape which is suitable for being produced by injection molding and which therefore lends itself especially to a mass production.

A further object of the present invention consists in providing a paper clip of such a shape and in providing such a method of producing the same that any air which might be enclosed in the liquid plastic during the injection thereof into the mold will not reduce the solidity of the final clip to any noticeable extent.

The present invention is based primarily -upon the nding that a paper clip which is cast with a uniform crosssectional area breaks very easily, and especially at the point where the material is poured into the die and also at such points where the air which is taken along by the liquid material might collect and form buibbles within the material. The danger of lbreakage due to such bubbles is especially great at the bent portions of the clip which Vare normally subjected to the greatest stresses and where usually the air bubbles have a particular tendency to accumulate and thus toY reduce the strength and effective thickness of the material.

Accordingly, it is an important feature of the present invention to provide a paper clip which consists of two substantially U-shaped clamping members which are interconnected by cross portions to form an endless strand, and to provide such a clip with reinforced portions at the most endangered points, especially at the central part connecting the two arms of each U-shaped clamping member, further at the point where during the molding process the liquid material has been injected into the mold, and at the point of the endless strand which is most remote from such injection point in the course of the iiow of plastic material. These reinforced portions are preferably made in the form of tongue-shaped projections which extend within the plane of the clip or obliquely thereto. The liquid material may then flow into the mold without resulting in any constrictions and reductions of the crosssectional area of the material. Furthermore, if during the injection of the liquid material into the mold, the same should pick up any air and push the same in the form of an air bubble to the remotest point from the point of injection, such air bubble may collect at such remotest point without danger that the solidity of the paper clip will thereby be reduced since this point is likewise located within such an enlarged portion.

A further object of the invention consists in providing a paper clip of `a cross-sectional shape which permits the clip to be easily slipped over the edge portions of papers,

files and the like, but prevents it from sliding off these papers. For attaining this object the paper clip according to the invention is preferably designed so that the longitudinally extending arms of the two clamping members thereof act as torsion bars, while the transverse parts connecting these longitudinal parts are made as rigid as possible to prevent them from being bent. The clamping arms may 'be further provided with spikelike or toothlike projections which may press into the papers after the clip is slipped thereon, but which preferably are designed so as not to 'act upon the papers until after the clamping arms have been twisted about their own axes when the two clamping members are wedged apart by being slipped upon the papers.

The molding operation and the usev of plastics also permits the paper clips to be easily provided with tab-like extensions Iand/or to be made of different colors. This permits the papers or other objects to be marked or to be distinguished from one another. The clips may also be made of transparent plastic so that when attached to any papers, any printing, writing or the like on these papers underneath the clips may be easily read through the Iclips.

Further objects, features, and advantages of the present invention will be apparent from the following detailed description thereof, particularly when read with reference to the accompanying drawings, in which- FIG. l shows a plan View of one embodiment of the paper clip according to the invention;

FIG. 2 shows a longitudinal section taken along line 2-2 of FIG. l;

FIG. 3 shows a cross section taken along line 3-3 of FIG. l;

FIG. 4 shows a plan view of -a modiication of the invention;

FIG. 5 shows a cross section of a paper clip according to the invention as taken, for example, along line 55 of FIG. l fbut on a slightly larger scale.

FIG. 6 shows a cross section similar to FIG. 5 but with a number of papers inserted between the arms of the clip;

FIGS. 7, 8, 9, and 10 show plan views of further modiiications of the invention; while FIG. 11 shows a plan view of a mold for casting a plurality of paper clips simultaneously.

Referring to the drawings, and rst particularly to FIGS. 1 to 3, the paper clip according to the invention consists of an outer clamping member 10 consisting of the two arms 10a and 10b and a curved crossbar 10c connecting these arms and an inner clamping member 11 consisting of the two arms 11a and 11b and a curved cross portion 11C connecting arms 11a and 11b. The two clamping members 10 and 11 which are disposed within the same plane are connected with each other by two cross portions 12a and 12b having a larger crosssectional area than arms 10a, 10b, and 11a, 11b, and together form an endless pin or rod. The curved crossbar 10c is provided with an inwardly extending tongue-shaped projection 13 at the point opposite to the inlet portion 13a Where thematerial was injected into the individual mold cavity during the molding process. This tongueshaped projection 13 may be disposed either within the same plane as the clip arms or slightly obliquely thereto so as to exert an increased gripping action upon the papers over which the clip is slipped. The curved cross portion 11C is likewise made of an enlarged cross-sectional area and may therefore take up an air bubble 14, as indicated in FIG. 1, without any noticeable loss in the solidity of the material. Such an air bubble may easily form while the clip is being cast, entering with the liquid material into the individual mold at the inlet point 13a, and being pushed by the material along the mold channels until it settles at the remotest point of the flow, namely, at the curved cross portion 11C between the inner arms 11a and 11b, where the material meets when coming from both sides. This enlarged portion which is adapted to take up such a possible air bubble 14 may also be made in the form of a tongue-shaped or pocket-shaped projection 15 on the cross portion 11C, for example, as illustrated in FIG. 4.

In the molding operation the wider portion 13 in the mold cavity has the advantage that the material flowing through inlet 13a in the direction shown in FIG. l by the arrow x can easily divide and flow toward both sides without causing any reduction in the cross-sectional area at the inlet side as occurs when such enlargement 13 is not provided.

FIG. 2 illustrates the wedgelike shape of the clamping arms tapering gradually from the lower to the upper end. While at the upper part of the clip near the upper cross portions 12a and 12b the arms 10a, 1Gb, and 11a, 11b have a substantially circular cross section, they gradually atten out in the downward direction and there assume a ilatter, substantially rectangular cross section. Due to this wedge-shaped construction, the clips do not add much to the thickness of the papers upon which they are slipped, but have Va very great strength at the points where they are subjected to the greatest stresses, namely, at the bending points 12a and 12b which, by being of a greater width, also prevent lateral distortion of the two pairs of arms relative to each other. The two clamping members and 11 can therefore be easily separated suficiently to be slipped over a set of papers and will then exert a very secure clamping action thereon.

As illustrated in FIG. 5, one or both pairs of arms 10a, 10b, and 11a, 11b may also be provided with spikelike or toothlike projections 16 which, if provided on both pairs extend outwardly from opposite sides, and on the released clip preferably not in a direction vertical to the plane of the clip but slightly inwardly in the peripheral direction of each arm so as to stand slightly at an angle so that, when the clip is slipped on a set of papers, as illustrated in FIG. 6, and the arms of both pairs are thereby twisted relative to each other about their longitudinal axes, the toothlike projections 16 will turn to a substantially vertical position relative to the plane of the clip and pass or bite into the papers.

If desired, the clips may also be provided with tablike extensions 17, as illustrated in FIG. 7, which are preferably integral with the clips and may be used for marking or identifying the papers or files upon which they are clipped. These extensions 17 also prevent a distortion of the clips Similar to the cross portions 12a and 12b, as shown in FIGS. 1, 2, and 4. This clip likewise has an enlarged tonguelike portion opposite to gate 13a, and another enlarged portion 18 for taking up an enclosed air bubble.

The paper clip may be made in Various shapes, that is, for example, in the oblong rectangular shape as shown in FIGS. 1, 2, 4, 7, and l0, or in a substantially circular shape, as shown in FIG. 8, or a triangular shape, as shown in FIG. 9. The enlargements or projections for increasing the cross-sectional area of the respective clips at the point of collection of a possible air bubble are indicated in FIGS. 8, 9, and 10 at 19, 21, and 23, respectively, and those at their upper bending points at 20 and 22 in FIGS. 8 and 9, respectively.

FIG. l1 illustrates the simultaneous casting of a larger number of paper clips within a single mold 24. 'Ihe plastic is injected in a liquid condition through the main inlet opening into the common distributing channel 25 from which it flows through the individual tapering inlets 26 into the individual mold cavities 27 in which the paper clips are formed. As already described, the enlargements 13 opposite to inlets 26 insure that the cross-sectional area of the clips will not be weakened at this point, While any air which might be taken along by the ow of material 4 will collect at the most remote points 14' where it will not exert any harmful effects because of the greater width or tonguelike shape of the cross portions.

Instead of making the inlets 26 to the individual mold cavities of a tapering shape as shown at the left side of FIG. 1l, they may also be of a semi-circular or other suitable shape, as indicated at 26a at the right side of FIG. 1l.

Although my invention has been illustrated and described with reference to the preferred embodiments thereof, I wish to have it understood that it is in no way limited to the details of such embodiments, but is capable of numerous modifications within the scope of the appended claims.

Having thus fully disclosed my invention, what I claim 1. A paper clip of elastically deformable synthetic material, comprising, a substantially U-shaped elongated outer clamping member including a pair of outer arms, a substantially U-shaped elongated inner clamping member including a pair of inner arms located in the sp-ace within said outer clamping member with the ends of said inner arms and `outer arms, respectively, located next to each other, and a pair of connecting portions, each connecting the end of one of said outer arms with the adjacent end of one of said inner arms, respectively, said connecting portions having a cross-section in a direction parallel to said arms greater than the cross-section of said arms, so that when said outer clamping member is bent relative to said inner clamping member the bending will resiliently occur mainly within the respective arms themselves.

2. A paper clip of elastically `deformable synthetic material, comprising, a substantially U-shaped elongated outer clamping member including a pair of outer arms, a substantially U-shaped elongated inner clamping member including a pair of inner arms located in the space within said outer clamping member with the ends of said inner arms and outer arms, respectively, located next to each other, and a pair of connecting portions, each connecting the end of one `of said outer arms with the adjacent end of one of said inner arms, respectively, said connecting portions having a cross-section in a direction parallel to said arms greater than the cross-section of said arms, so that when said outer clamping member is bent relative to said inner clamping member the -bending will resiliently occur mainly within the respective arms themselves.

3. A paper clip of elastically deformable synthetic material, comprising, a substantially arcuate elongated outer clamping member including a pair of outer arms a substantially arcuate elongated inner clamping member including a pair of inner arms located in the space within said outer clamping member with the ends of said inner arms and outer arms, respectively, located next to each other, and a pair of connecting portions, each connecting the end of one of said outer arms with the adjacent end of one of said inner arms, respectively, said connecting portions having a cross-section in a direction parallel to said arms greater than the cross-section of said arms, S0 that when said outer clamping member is bent relative to said inner clamping member the bending will resiliently occur mainly within the respective arms themselves.

4. A paper clip of elastically deformable synthetic material, comprising, a substantially U-shaped elongated outer clamping member including a pair of outer arms, an outer connecting portion forming the base of said U-shaped outer clamping member, a substantially U- shaped elongated inner clamping member including a pair of inner arms located in the space within said outer clamping mem-ber with the ends of said inner arms and outer arms, respectively, located next to each other, an inner connecting portion forming the base of said U- shaped inner clamping member, and a pair of connecting portions, each connecting the end of one of said outer arms with the adjacent end of one of said inner arms, re-

spectively, all of said connecting portions havin ga crosssection in a direction parallel to said arms greater than the cross-section of said arms, so that when said outer clamping member is bent relative to said inner clamping member the bending will resiliently occur mainly Within the respective arms themselves.

5. A paper clip of elastically deformable synthetic material, comprising, a substantially U-shaped elongated outer clamping member including a pair of outer arms, an outer connecting portion of arcuate shape forming the base of said U-shaped outer clamping member, a substantially U-shaped elongated inner clamping member including a pair of inner arms located in the space Within said outer clamping member with the ends of said inner arms and outer arms, respectively, located next to each other, an inner connecting portion of arcuate shape forming the base of said U-shaped inner clamping member, and a pair of connecting portions, each connecting the end of one of said outer arms With the adjacent end of one of said inner arms, respectively, all of said connecting portions having a cross-section in a direction parallel to said arms greater than the cross-section of said arms, so that when said outer clamping member is bent relative to said inner clamping member the bending Will resiliently occur mainly Within the respective arms themselves.

6. A paper clip of elastically deformable synthetic material, comprising, a substantially U-shaped elongated outer clamping member including a pair of outer arms, a substantially U-shaped elongated inner clamping member including a pair of inner arms located in the space within said outer clamping member with the ends of said inner arms and outer arms, respectively, located next to each other, and a pair of connecting portions, each connecting the end of one of said outer arms with the adjacent end of one of said inner arms, respectively, said fconnecting portions having a cross-section in -a direction parallel to said arms greater than the cross-section of said arms, said clamping members and said connecting portions extending substantially in one plane, so that when said outer clamping member is -bent relative to said inner clamping member the lbending Will resiliently occur mainly Within the respective arms themselves.

7. A paper clip of elastically deformable synthetic material, comprising, a substantially U-shaped elongated outer clamping member including a pair of outer arms, an outer connecting portion forming the base of said U- shaped outer clamping member, a substantially U-shaped elongated inner clamping member including a pair of inner arms located in the space Within said outer clamping member with the ends of said inner arms and outer arms, respectively, located next to each other, an inner connecting portion forming the base of said U-shaped inner clamping member, said outer connecting portion having a projection extending toward said inner connecting portion, and a pair of connecting portions, each connecting the end of one of said outer arms with the adjacent end of one of said inner arms, respectively, all of said connecting portions having a cross-section in a direction parallel to said arms greater than the cross-section of said arms, so that when said `outer clamping member is bent relative to said inner clamping member the bending will resiliently occur mainly Within the respective arms themselves.

8. A paper clip of elastically deformable synthetic material, comprising, a substantially U-shaped elongated outer clamping member including a pair of outer arms, an outer connecting portion forming the base of said U- shaped outer clamping member, a substantially U-shaped elongated inner clamping member including a pair of inner arms located in the space Within said outer clamping member with the ends of said inner arms and outer arms, respectively, located next to each other, an inner connecting portion forming the base of said U-shaped inner clamping member, said inner connecting portion having a projection extending toward said outer connecting portion, and a pair of connecting portions, each connecting the end of one of said outer arms With the adjacent end of one of said inner arms, respectively, all of said connecting portions having a cross-section in a direction parallel to said -arms greater than the cross-section of said arms, so that when said outer clamping member is bent relative to said inner clamping member the bending Will resiliently occur mainly within the respective arms themselves.

9. A paper clip of elastically deformable synthetic material, comprising, a substantially U-shaped elongated outer clamping member including a pair of outer arms, an outer connecting portion forming the base of said U- shaped outer clamping member, a substantially U-shaped elongated inner `clamping member including a pair of inner arms located in the space Within said outer clamping member -with the ends of said inner arms and outer arms, respectively, located next to each other, an inner connecting portion forming the base of said U-shaped inner clamping member, said outer connecting portion having a projection extending toward said inner connecting portion, said inner connecting portion having a projection extending toward said outer connecting portion, and a pair of connecting portions, each connecting the end of one of said outer arms with the adjacent end of one of said inner arms, respectively, all of said connecting portions having a cross-section in a direction parallel to said arms greater than the cross-section of said arms, so that when said outer clamping member is bent relative to said inner clamping member the bending Will resiliently occur mainly Within the respective arms themselves.

l0. A paper clip of elastically deformable synthetic material, comprising, a substantially U-shaped elongated outer clamping member including a pair of outer arms of a circular cross-section, a substantially U-shaped elongated inner clamping member including a pair of inner arms of a circular cross-section and located in the space Within said outer clamping member yWith the ends of said inner arms and outer arms, respectively, located next to each other, and a pair of connecting portions, each connecting the end of one of said outer arms with the adjacent end of one of said inner arms, respectively, said connecting portions having a cross-section in a direction parallel to said arms greater than the cross-section of said arms, so that When said outer clamping member is bent relative to said inner clamping member the bending will resiliently occur mainly Within the respective arms themselves.

ll. A paper clip of elastically deformable synthetic material, comprising, a substantially U-shaped elongated outer clamping member including a pair of outer arms, a substantially U-shaped elongated inner clamping member including a pair of inner arms located in the space Within said outer clamping member with the ends of said inner arms and outer arms, respectively, located next to each other, a pair of connecting portions, each connecting the end of one of said outer armsl with the adjacent end of one of said inner arms, respectively, said clamping members and said connecting portions extending substantially in one plane, and said inner arms having projections formed thereon spaced from each other, extending toward said outer arms and at an acute angle toward said one plane.

l2. A paper clip of elastically deformable synthetic material, comprising, a substantially U-shaped elongated outer clamping member including a pair of outer arms, a substantially U-shaped elongated inner clamping member including a pair of inner arms located in the space within lsaid outer clamping member with t-he ends of said inner arms and outer arms, respectively, located next to each other, a pair of connecting portions, each connecting the end of one of said outer arms with the adjacent end of one of said inner arms, respectively, said clamping members and said connecting portions extending substantially in one plane, and said outer arms having projections formed thereon spaced from each other extending toward said inner arms and at an acute angle toward saide one plane.

13. A paper clip of elastically deformable synthetic material, comprising, a substantially U-sha-ped elongated outer clamping member including a pair of outer arms extending parallel to each other, an outer connecting portion of arcuate shape forming the base of said U-shaped outer clamping member, a substantial-1y U-shaped elongated inner clamping member including a pair of inner arms and located in the space within said outer clamping member with the ends of said inner arms and outer arms, respectively, located next to each other, said inner arms extending parallel to each other, an inner connecting portion of arcuate shape forming the base of said U-shaped inner clamping member, a pair of connecting portions, each connecting the end of one of said outer arms With the adjacent end of one of said inner arms, respectively, said clamping members and said connecting portions extending substantially in one plane, said inner arms having projections formed thereon spaced from each other, extending toward said outer arms and at an acute angle toward said one plane, and said outer arms having projections formed thereon spaced from each other extending toward said inner arms and at an acute angle toward said one plane.

14. A paper clip of elastically deformable synthetic material, comprising, a substantially U-shaped elongated outer clamping member including a pair of outer arms of a circular cross-section and extending parallel to each other, an outer connecting portion of arcuate shape forming the base of said U-shaped outer clamping member, a substantially U-shaped elongated inner clamping member including a pair of inner arms of a circular crosssection and located in the space within said outer clamping member with the ends of said inner arms and outer arms, respectively, located next to each other, said inner arms extending parallel to each other, an inner connecting portion of arcuate shape forming the base of said U-shaped inner clamping member, said outer connecting portion having a projection extending toward said inner connecting portion, :said inner connecting portion having a projection extending toward said outer connecting portion, a pair of connecting portions, each connecting the end of one of said outer arms with the adjacent end of one of said inner arms, respectively, said clamping members and said connecting portions extending substantially in one plane, said inner arms having projections formed thereon spaced from each other, extending toward said outer arms and at an acute angle toward said one plane, and said outer arms having projections formed thereon extending toward said inner arms and at an acute angle toward said one plane all of said connecting portions having a cross-section at least in part larger than the cross-sections of said arms so that When said outer clamping member is bent relative to said inner clamping member the bending will resiliently occur mainly within the respective arms themselves.

l5. A paper clip of elastically deformable synthetic material, comprising, a substantially U-shaped elongated outer clamping member including a pair of outer arms having each a length being a multiple of its width, and an arcuate outer connecting member forming the base of the said U-shaped outer clamping member and joined to said outer arms with portions of substantially uniform curvature; a substantially U-shaped elongated inner clamping member including a pair of inner arms having each a ylength being a multiple of its Width, and an arcuate inner connecting member forming the base of the U-shaped inner clamping member and joined to said inner arms -With portions of substantially uniform curvature, said inner clamping member being located in the space Within said outer clamping member and substantially in a com-mon plane therewith with the ends of ysaid inner and outer arms, respectively, located next to each other; and a pair of arcuate connecting portions each connecting the end of one of said outer arms with the adjacent end of one of said inner arms, respectively, in a continuous manner With the ends of said arms extending respectively in direction of the ends of the respective connecting portion, vsaid connecting portions having a crosssection in a direction parallel to said arms larger than the cross-section of said arms, so that ywhen said clamping members are bent relative to each other the bending Will resilient-ly occur mainly within said arms.

16'. A paper clip in the form of an endless strand of plastic material and comprising a substantially U-shaped elongated outer clamping member including a pair of outer elongated arms and an arcuate outer connecting portion forming the base of said U-shaped outer clamping member and joining said outer arms; a substantially U-shaped elongated inner clamping member including a pair of inner elongated arms and an arcuate inner connecting portion forming the base of said U-shaped inner clam-ping member and joining said inner arms, said inner clamping member being lio-cated in the space within said outer clamping member and substantially in a common plane therewith with the ends of said inner and outer arms located next to each other; a pair of curved connecting portions, each connecting the end of one of said outer arms with the adjacent end of one of said inner arms; and at least one projection spaced from said curved connecting portions and integral `with one of said clamping members and projecting therefrom out of said plane in which said clamping member and the connecting portions thereof are located.

References Cited in the file of this patent UNITED STATES PATENTS 649,338 McGill May 8, 1900 1,878,861 Krasnow Sept. 20, 1932 2,100,708 Blakley Nov. 30, 1937 2,199,144 Tegarty Apr. 30, 1940 2,448,676 MacMillin et al Sept. 7, 1948 2,609,629 Hubbard Sept. 9, 1952 

